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<header class="api-profile-header">
  <h1 class="api-profile-header-heading">$interpolate</h1>
  <ol class="api-profile-header-structure naked-list step-list">
    
  <li>
    <a href="api/ng/provider/$interpolateProvider">- $interpolateProvider</a>
  </li>

    <li>
      - service in module <a href="api/ng">ng</a>
    </li>
  </ol>
</header>



<div class="api-profile-description">
  <p>Compiles a string with markup into an interpolation function. This service is used by the
HTML <a href="api/ng/service/$compile">$compile</a> service for data binding. See
<a href="api/ng/provider/$interpolateProvider">$interpolateProvider</a> for configuring the
interpolation markup.</p>
<pre><code class="lang-js">var $interpolate = ...; // injected
var exp = $interpolate(&#39;Hello {{name | uppercase}}!&#39;);
expect(exp({name:&#39;Angular&#39;})).toEqual(&#39;Hello ANGULAR!&#39;);
</code></pre>
<p><code>$interpolate</code> takes an optional fourth argument, <code>allOrNothing</code>. If <code>allOrNothing</code> is
<code>true</code>, the interpolation function will return <code>undefined</code> unless all embedded expressions
evaluate to a value other than <code>undefined</code>.</p>
<pre><code class="lang-js">var $interpolate = ...; // injected
var context = {greeting: &#39;Hello&#39;, name: undefined };

// default &quot;forgiving&quot; mode
var exp = $interpolate(&#39;{{greeting}} {{name}}!&#39;);
expect(exp(context)).toEqual(&#39;Hello !&#39;);

// &quot;allOrNothing&quot; mode
exp = $interpolate(&#39;{{greeting}} {{name}}!&#39;, false, null, true);
expect(exp(context)).toBeUndefined();
context.name = &#39;Angular&#39;;
expect(exp(context)).toEqual(&#39;Hello Angular!&#39;);
</code></pre>
<p><code>allOrNothing</code> is useful for interpolating URLs. <code>ngSrc</code> and <code>ngSrcset</code> use this behavior.</p>
<h4 id="escaped-interpolation">Escaped Interpolation</h4>
<p>$interpolate provides a mechanism for escaping interpolation markers. Start and end markers
can be escaped by preceding each of their characters with a REVERSE SOLIDUS U+005C (backslash).
It will be rendered as a regular start/end marker, and will not be interpreted as an expression
or binding.</p>
<p>This enables web-servers to prevent script injection attacks and defacing attacks, to some
degree, while also enabling code examples to work without relying on the
<a href="api/ng/directive/ngNonBindable">ngNonBindable</a> directive.</p>
<p><strong>For security purposes, it is strongly encouraged that web servers escape user-supplied data,
replacing angle brackets (&lt;, &gt;) with &amp;lt; and &amp;gt; respectively, and replacing all
interpolation start/end markers with their escaped counterparts.</strong></p>
<p>Escaped interpolation markers are only replaced with the actual interpolation markers in rendered
output when the $interpolate service processes the text. So, for HTML elements interpolated
by <a href="api/ng/service/$compile">$compile</a>, or otherwise interpolated with the <code>mustHaveExpression</code> parameter
set to <code>true</code>, the interpolated text must contain an unescaped interpolation expression. As such,
this is typically useful only when user-data is used in rendering a template from the server, or
when otherwise untrusted data is used by a directive.</p>
<p>

<div>
  <a ng-click="openPlunkr('examples/example-example109', $event)" class="btn pull-right">
    <i class="glyphicon glyphicon-edit">&nbsp;</i>
    Edit in Plunker</a>

  <div class="runnable-example"
      path="examples/example-example109">

  
    <div class="runnable-example-file" 
      name="index.html"
      language="html"
      type="html">
      <pre><code>&lt;div ng-init=&quot;username=&#39;A user&#39;&quot;&gt;&#10;  &lt;p ng-init=&quot;apptitle=&#39;Escaping demo&#39;&quot;&gt;{{apptitle}}: \{\{ username = &quot;defaced value&quot;; \}\}&#10;    &lt;/p&gt;&#10;  &lt;p&gt;&lt;strong&gt;{{username}}&lt;/strong&gt; attempts to inject code which will deface the&#10;    application, but fails to accomplish their task, because the server has correctly&#10;    escaped the interpolation start/end markers with REVERSE SOLIDUS U+005C (backslash)&#10;    characters.&lt;/p&gt;&#10;  &lt;p&gt;Instead, the result of the attempted script injection is visible, and can be removed&#10;    from the database by an administrator.&lt;/p&gt;&#10;&lt;/div&gt;</code></pre>
    </div>
  

    <iframe class="runnable-example-frame" src="examples/example-example109/index.html" name="example-example109"></iframe>
  </div>
</div>


</p>

</div>




<div>
  
  <h2 id="dependencies">Dependencies</h2>
  <ul>
    <li><a href="api/ng/service/$parse"><code>$parse</code></a></li><li><a href="api/ng/service/$sce"><code>$sce</code></a></li>
  </ul>
  

    

  <h2 id="usage">Usage</h2>
    
      <p><code>$interpolate(text, [mustHaveExpression], [trustedContext], [allOrNothing]);</code></p>


    

    
<section class="api-section">
  <h3>Arguments</h3>

<table class="variables-matrix input-arguments">
  <thead>
    <tr>
      <th>Param</th>
      <th>Type</th>
      <th>Details</th>
    </tr>
  </thead>
  <tbody>
    
    <tr>
      <td>
        text
        
        
      </td>
      <td>
        <a href="" class="label type-hint type-hint-string">string</a>
      </td>
      <td>
        <p>The text with markup to interpolate.</p>

        
      </td>
    </tr>
    
    <tr>
      <td>
        mustHaveExpression
        
        <div><em>(optional)</em></div>
      </td>
      <td>
        <a href="" class="label type-hint type-hint-boolean">boolean</a>
      </td>
      <td>
        <p>if set to true then the interpolation string must have
   embedded expression in order to return an interpolation function. Strings with no
   embedded expression will return null for the interpolation function.</p>

        
      </td>
    </tr>
    
    <tr>
      <td>
        trustedContext
        
        <div><em>(optional)</em></div>
      </td>
      <td>
        <a href="" class="label type-hint type-hint-string">string</a>
      </td>
      <td>
        <p>when provided, the returned function passes the interpolated
   result through <a href="api/ng/service/$sce#getTrusted">$sce.getTrusted(interpolatedResult,
   trustedContext)</a> before returning it.  Refer to the <a href="api/ng/service/$sce">$sce</a> service that
   provides Strict Contextual Escaping for details.</p>

        
      </td>
    </tr>
    
    <tr>
      <td>
        allOrNothing
        
        <div><em>(optional)</em></div>
      </td>
      <td>
        <a href="" class="label type-hint type-hint-boolean">boolean</a>
      </td>
      <td>
        <p>if <code>true</code>, then the returned function returns undefined
   unless all embedded expressions evaluate to a value other than <code>undefined</code>.</p>

        
      </td>
    </tr>
    
  </tbody>
</table>

</section>
    
    <h3>Returns</h3>
<table class="variables-matrix return-arguments">
  <tr>
    <td><a href="" class="label type-hint type-hint-function">function(context)</a></td>
    <td><p>an interpolation function which is used to compute the
   interpolated string. The function has these parameters:</p>
<ul>
<li><code>context</code>: evaluation context for all expressions embedded in the interpolated text</li>
</ul>
</td>
  </tr>
</table>

  
<h2>Methods</h2>
<ul class="methods">
  <li id="startSymbol">
    <h3><p><code>startSymbol();</code></p>

</h3>
    <div><p>Symbol to denote the start of expression in the interpolated string. Defaults to <code>{{</code>.</p>
<p>Use <a href="api/ng/provider/$interpolateProvider#startSymbol"><code>$interpolateProvider.startSymbol</code></a> to change
the symbol.</p>
</div>

    

    
    
    
    <h4>Returns</h4>
    <table class="variables-matrix return-arguments">
  <tr>
    <td><a href="" class="label type-hint type-hint-string">string</a></td>
    <td><p>start symbol.</p>
</td>
  </tr>
</table>
    

  </li>
  
  <li id="endSymbol">
    <h3><p><code>endSymbol();</code></p>

</h3>
    <div><p>Symbol to denote the end of expression in the interpolated string. Defaults to <code>}}</code>.</p>
<p>Use <a href="api/ng/provider/$interpolateProvider#endSymbol"><code>$interpolateProvider.endSymbol</code></a> to change
the symbol.</p>
</div>

    

    
    
    
    <h4>Returns</h4>
    <table class="variables-matrix return-arguments">
  <tr>
    <td><a href="" class="label type-hint type-hint-string">string</a></td>
    <td><p>end symbol.</p>
</td>
  </tr>
</table>
    

  </li>
  </ul>
  
  



  
</div>


